A conventional connection device for locking a screw bit to a tube generally includes a bead which movably engaged with a hole defined through a wall of the tube so as to contact against an outer surface of the screw bit to secure the screw bit. When the screw bit is to be removed from the tube, the bead is slightly moved outward from the hole so that the user pulls the screw bit out from the tube. It is experienced that the screw bit might be firmly engaged with the tube during operation so that the user is difficult to pull the screw bit out, especially when oil or grease are attached on the user's fingers. Some connection for locking the screw includes multiple parts and a complicated structure which increases the manufacturing cost.
The present invention intends to provide a device for locking a crew bit firmly to a tube and for biasing the screw bit from the tube.